Method for setting automatic gun triggering parameters in automated spray coating systems

Abstract

A method for controlling triggering of spray guns in an automatic spray coating system, includes a hand-held pendant having input controls for entering spray gun “on” and spray gun “off” control parameters based upon observation of parts as they are conveyed past the spray guns by a conveyor. Gun triggering controls for optimized spray patterns, including extended and restricted spray patterns and combinations thereof, are entered and saved in a gun triggering controller according to an operator's inputs which include START SPRAY, STOP SPRAY, SAVE and SET PICKOFF controls. Multiple gun control parameters are stored as unique part coating recipes in the controller and are executable in look-ahead sequence based upon part identification as parts are conveyed toward the spray guns. The multiple gun control parameters are calculated by the controller from a fixed Pickoff distance from a part identification sensor to the spray guns.

The invention claimed is:  
     
       1. A method of triggering one or more spray guns in an automatic spray coating system having at least one spray gun located proximate to a conveyor on which a part to be coated is conveyed past the spray gun, the method comprising the steps of: 
       sensing a location of said part as it is conveyed on the conveyor relative to a reference point,  
       determining a first distance of said part at a start spray position relative to said reference point;  
       determining a second distance of said part at a stop spray position relative to said reference point;  
       determining a front edge spray gun control parameter by combining said first distance with a pickoff distance, said pickoff distance being defined as the distance from the gun to the sensor;  
       determining a back edge spray gun control parameter by combining said second distance with said pickoff distance and a length of said part; and  
       automatically coating said part conveyed past the spray gun according to the front edge spray and the back edge spray gun triggering control parameters.  
     
     
       2. The method of  claim 1  further comprising the steps of: 
       selectively setting a part location at which a leading edge of the part is generally aligned with the spray gun to define a Pickoff gun triggering control parameter by operation of a SET PICKOFF input control of the control input device, and  
       storing the selected gun triggering control parameter in the control system by operation of a SAVE input control of the control input device.  
     
     
       3. The method of  claim 2  further comprising the steps of selectively entering multiple gun triggering control parameters to define multiple control recipes for different types of parts, and storing the multiple gun triggering control parameters in the control system, and wherein more than one gun triggering control uses the same PICKOFF input control. 
     
     
       4. The method of  claim 3  further comprising the steps of assigning a recipe number to each of the control recipes stored in the control system, and coating parts identified by the system according to recipe numbers which correspond to identified parts. 
     
     
       5. The method of  claim 2  wherein the front edge spray gun control parameter is determined by subtracting the first signal from the pickoff distance. 
     
     
       6. The method of  claim 2  wherein the back edge spray gun control parameter is determined by subtracting the length of said part from the second distance, and subtracting the pickoff distance from the difference of the length of said part subtracted from the second distance. 
     
     
       7. The method of  claim 4  further comprising the step of loading a part coating recipe for a subsequent part during coating of a preceding part. 
     
     
       8. The method of  claim 1  further comprising the step of associating pressure and voltage parameters with a gun control parameter. 
     
     
       9. The method of  claim 1  wherein selected gun triggering control parameters are stored for operation of selected guns of an automatic spray coating system. 
     
     
       10. The method of  claim 3  including the step of copying control recipes for execution by selected spray guns of an automatic spray coating system. 
     
     
       11. A method for determining gun control triggering parameters for initiating and terminating coating material through a spray gun onto an article to be coated, the method comprising the following steps: 
       sensing the location of said article relative to a reference point;  
       determining a first distance of said article at a start spray position relative to said reference point, and determining a second distance of said article at a stop spray position relative to said reference point;  
       determining a front edge spray gun control parameter by combining said first distance with a pickoff distance, said pickoff distance being defined as the distance from the gun to the sensor;  
       determining a back edge spray gun control parameter by combining said second distance with said pickoff distance and a length of said article to be coated.  
     
     
       12. The method of  claim 11  wherein said front edge spray gun control parameter and said back edge spray gun control parameter are independent of each other. 
     
     
       13. The method of  claim 11  wherein said first and second distances are independent of each other. 
     
     
       14. The method of  claim 11  wherein said reference point is said spray gun.